A novel mechanism of ferroptosis inhibition-enhanced atherosclerotic plaque stability: YAP1 suppresses vascular smooth muscle cell ferroptosis through GLS1.

Atherosclerosis is a leading cause of cardiovascular diseases (CVDs), often resulting in major adverse cardiovascular events (MACEs), such as myocardial infarction and stroke due to the rupture or erosion of vulnerable plaques. Ferroptosis, an iron-dependent form of cell death, has been implicated in the development of atherosclerosis. Despite its involvement in CVDs, the specific role of ferroptosis in atherosclerotic plaque stability remains unclear. In this study, we confirmed the presence of ferroptosis in unstable atherosclerotic plaques and demonstrated that the ferroptosis inhibitor ferrostatin-1 (Fer-1) stabilizes atherosclerotic plaques in apolipoprotein E knockout (Apoe-/-) mice. Using bioinformatic analysis combining RNA sequencing (RNA-seq) with single-cell RNA sequencing (scRNA-seq), we identified Yes-associated protein 1 (YAP1) as a potential key regulator of ferroptosis in vascular smooth muscle cells (VSMCs) of unstable plaques. In vitro, we found that YAP1 protects against oxidized low-density lipoprotein (oxLDL)-induced ferroptosis in VSMCs. Mechanistically, YAP1 exerts its anti-ferroptosis effects by regulating the expression of glutaminase 1 (GLS1) to promote the synthesis of glutamate (Glu) and glutathione (GSH). These findings establish a novel mechanism where the inhibition of ferroptosis promotes the stabilization of atherosclerotic plaques through the YAP1/GLS1 axis, attenuating VSMC ferroptosis. Thus, targeting the YAP1/GLS1 axis to suppress VSMC ferroptosis may represent a novel strategy for preventing and treating unstable atherosclerotic plaques.

Hydrostatic pressure drives sprouting angiogenesis via adherens junction remodelling and YAP signalling.

Endothelial cell physiology is governed by its unique microenvironment at the interface between blood and tissue. A major contributor to the endothelial biophysical environment is blood hydrostatic pressure, which in mechanical terms applies isotropic compressive stress on the cells. While other mechanical factors, such as shear stress and circumferential stretch, have been extensively studied, little is known about the role of hydrostatic pressure in the regulation of endothelial cell behavior. Here we show that hydrostatic pressure triggers partial and transient endothelial-to-mesenchymal transition in endothelial monolayers of different vascular beds. Values mimicking microvascular pressure environments promote proliferative and migratory behavior and impair barrier properties that are characteristic of a mesenchymal transition, resulting in increased sprouting angiogenesis in 3D organotypic model systems ex vivo and in vitro. Mechanistically, this response is linked to differential cadherin expression at the adherens junctions, and to an increased YAP expression, nuclear localization, and transcriptional activity. Inhibition of YAP transcriptional activity prevents pressure-induced sprouting angiogenesis. Together, this work establishes hydrostatic pressure as a key modulator of endothelial homeostasis and as a crucial component of the endothelial mechanical niche.

Metabolic and transcriptomic reprogramming during contact inhibition-induced quiescence is mediated by YAP-dependent and YAP-independent mechanisms.

Metabolic rewiring during the proliferation-to-quiescence transition is poorly understood. Here, using a model of contact inhibition-induced quiescence, we conducted 13C-metabolic flux analysis in proliferating (P) and quiescent (Q) mouse embryonic fibroblasts (MEFs) to investigate this process. Q cells exhibit reduced glycolysis but increased TCA cycle flux and mitochondrial respiration. Reduced glycolytic flux in Q cells correlates with reduced glycolytic enzyme expression mediated by yes-associated protein (YAP) inhibition. The increased TCA cycle activity and respiration in Q cells is mediated by induced mitochondrial pyruvate carrier (MPC) expression, rendering them vulnerable to MPC inhibition. The malate-to-pyruvate flux, which generates NADPH, is markedly reduced by modulating malic enzyme 1 (ME1) dimerization in Q cells. Conversely, the malate dehydrogenase 1 (MDH1)-mediated oxaloacetate-to-malate flux is reversed and elevated in Q cells, driven by high mitochondrial-derived malate levels, reduced cytosolic oxaloacetate, elevated MDH1 levels, and a high cytoplasmic NAD+/NADH ratio. Transcriptomic analysis revealed large number of genes are induced in Q cells, many of which are associated with the extracellular matrix (ECM), while YAP-dependent and cell cycle-related genes are repressed. The results suggest that high TCA cycle flux and respiration in Q cells are required to generate ATP and amino acids to maintain de-novo ECM protein synthesis and secretion.

Activation of VGLL4 Suppresses Cardiomyocyte Maturational Hypertrophic Growth.

From birth to adulthood, the mammalian heart grows primarily through increasing cardiomyocyte (CM) size, which is known as maturational hypertrophic growth. The Hippo-YAP signaling pathway is well known for regulating heart development and regeneration, but its roles in CM maturational hypertrophy have not been clearly addressed. Vestigial-like 4 (VGLL4) is a crucial component of the Hippo-YAP pathway, and it functions as a suppressor of YAP/TAZ, the terminal transcriptional effectors of this signaling pathway. To develop an in vitro model for studying CM maturational hypertrophy, we compared the biological effects of T3 (triiodothyronine), Dex (dexamethasone), and T3/Dex in cultured neonatal rat ventricular myocytes (NRVMs). The T3/Dex combination treatment stimulated greater maturational hypertrophy than either the T3 or Dex single treatment. Using T3/Dex treatment of NRVMs as an in vitro model, we found that activation of VGLL4 suppressed CM maturational hypertrophy. In the postnatal heart, activation of VGLL4 suppressed heart growth, impaired heart function, and decreased CM size. On the molecular level, activation of VGLL4 inhibited the PI3K-AKT pathway, and disrupting VGLL4 and TEAD interaction abolished this inhibition. In conclusion, our data suggest that VGLL4 suppresses CM maturational hypertrophy by inhibiting the YAP/TAZ-TEAD complex and its downstream activation of the PI3K-AKT pathway.

UBR1 promotes anaplastic thyroid carcinoma progression via stabilizing YAP through monoubiquitylation.

Anaplastic thyroid carcinoma (ATC) is a highly aggressive human malignancy without effective treatment. Yes-associated protein (YAP) is a critical effector of the Hippo pathway, which is essential in thyroid carcinogenesis. However, the underlying mechanisms of aberrant YAP expression in ATC are not completely understood. Ubiquitylation-related enzyme siRNA screening identified the ubiquitin protein ligase E3 component n-recognin 1 (UBR1) as a stabilizer of YAP in ATC cells. UBR1 deficiency reduced YAP protein levels and its target gene expression. UBR1 directly interacted with YAP and promoted its monoubiquitylation, competitively suppressing its polyubiquitylation and resulting in extended protein half-life. UBR1 depletion reduced ATC cell proliferation and migration in vitro. Xenograft tumor studies also suggested that UBR1 knockdown suppressed ATC cell growth in vivo. Furthermore, exogenous YAP expression partially reversed the inhibitive effects of UBR1 depletion on ATC cell proliferation and migration. Our studies demonstrated that UBR1 directly interacts with YAP and stabilized it in a monoubiquitylation-dependent manner, consequently promoting ATC tumorigenesis, suggesting that UBR1 might be a potentially therapeutic target for ATC treatment.

The miRNAs 203a/210-3p/5001-5p regulate the androgen/androgen receptor/YAP-induced migration in prostate cancer cells.

BACKGROUND: Prostate cancer (PCa) patients with elevated level of androgen receptor (AR) correlate with higher metastatic incidence. Protein expression of AR and its target gene prostate-specific antigen (PSA) are elevated in metastatic prostate tumors as compared to organ-confined tumors. Androgen treatment or elevation of AR promotes metastasis of PCa in cell culture and murine model. However, under androgen depleted condition, AR suppressed cell mobility and invasiveness of PCa cells. Androgen deprivation therapy in PCa patients is associated with higher risk of cancer metastasis. We therefore investigated the dual roles of AR and miRNAs on PCa metastasis. METHODS: The PC-3AR (PC-3 cells re-expressing AR) and LNCaP cells were used as PCa cell model. Transwell migration and invasion assay, wound-healing assay, zebrafish xenotransplantation assay, and zebrafish vascular exit assay were used to investigate the role of AR and androgen on PCa metastasis. Micro-Western Array, co-immunoprecipitation and Immunofluorescence were applied to dissect the molecular mechanism lying underneath. The miRNA array, miRNA inhibitors or plasmid, and chromatin immunoprecipitation assay were used to study the role of miRNAs on PCa metastasis. RESULTS: In the absence of androgen, AR repressed the migration and invasion of PCa cells. When androgen was present, AR stimulated the migration and invasion of PCa cells both in vitro and in zebrafish xenotransplantation model. Androgen increased phospho-AR Ser81 and yes-associated protein 1 (YAP), decreased phospho-YAP Ser217, and altered epithelial-mesenchymal transition (EMT) proteins in PCa cells. Co-IP assay demonstrated that androgen augmented the interaction between YAP and AR in nucleus. Knockdown of YAP or treatment with YAP inhibitor abolished the androgen-induced migration and invasion of PCa cells, while overexpression of YAP showed opposite effects. The miRNA array revealed that androgen decreased hsa-miR-5001-5p but increased hsa-miR-203a and hsa-miR-210-3p in PC-3AR cells but not PC-3 cells. Treatment with inhibitors targeting hsa-miR-203a/hsa-miR-210-3p, or overexpression of hsa-miR-5001-5p decreased YAP expression as well as suppressed the androgen-induced migration and invasion of PCa cells. Chromatin immunoprecipitation (ChIP) assay demonstrated that AR binds with promoter region of has-miR-210-3p in the presence of androgen. CONCLUSIONS: Our observations indicated that miRNAs 203a/210-3p/5001-5p regulate the androgen/AR/YAP-induced PCa metastasis.

Aspirin attenuates the detrimental effects of TNF-α on BMMSC stemness by modulating the YAP-SMAD7 axis.

BACKGROUND: Bone marrow mesenchymal stem cells (BMMSCs) are commonly used for cell transplantation to treat refractory diseases. However, the presence of inflammatory factors, such as tumour necrosis factor-alpha (TNF-α), at the transplantation site severely compromises the stemness of BMMSCs, thereby reducing the therapeutic effect of cell transplantation. Aspirin (AS) is a drug that has been in use for over a century and has a wide range of effects, including the regulation of cell proliferation, multidirectional differentiation, and immunomodulatory properties of stem cells. However, it is still unclear whether AS can delay the damaging effects of TNF-α on BMMSC stemness. METHODS: This study investigated the effects of AS and TNF-α on BMMSC stemness and the molecular mechanisms using colony formation assay, western blot, qRT-PCR, and overexpression or knockdown of YAP and SMAD7. RESULTS: The results demonstrated that TNF-α inhibited cell proliferation, the expression of stemness, osteogenic and chondrogenic differentiation markers of BMMSCs. Treatment with AS was shown to mitigate the TNF-α-induced damage to BMMSC stemness. Mechanistic studies revealed that AS may reverse the damage caused by TNF-α on BMMSC stemness by upregulating YAP and inhibiting the expression of SMAD7. CONCLUSION: AS can attenuate the damaging effects of TNF-α on BMMSC stemness by regulating the YAP-SMAD7 axis. These findings are expected to promote the application of AS to improve the efficacy of stem cell therapy.

Hippo signaling pathway regulates Ebola virus transcription and egress.

Filovirus-host interactions play important roles in all stages of the virus lifecycle. Here, we identify LATS1/2 kinases and YAP, key components of the Hippo pathway, as critical regulators of EBOV transcription and egress. Specifically, we find that when YAP is phosphorylated by LATS1/2, it localizes to the cytoplasm (Hippo "ON") where it sequesters VP40 to prevent egress. In contrast, when the Hippo pathway is "OFF", unphosphorylated YAP translocates to the nucleus where it transcriptionally activates host genes and promotes viral egress. Our data reveal that LATS2 indirectly modulates filoviral VP40-mediated egress through phosphorylation of AMOTp130, a positive regulator of viral egress, but more surprisingly that LATS1/2 kinases directly modulate EBOV transcription by phosphorylating VP30, an essential regulator of viral transcription. In sum, our findings highlight the potential to exploit the Hippo pathway/filovirus axis for the development of host-oriented countermeasures targeting EBOV and related filoviruses.

Computational design and experimental confirmation of a disulfide-stapled YAP helixα1-trap derived from TEAD4 helical hairpin to selectively capture YAP α1-helix with potent antitumor activity.

Human Hippo signaling pathway is an evolutionarily conserved regulator network that controls organ development and has been implicated in various cancers. Transcriptional enhanced associate domain-4 (TEAD4) is the final nuclear effector of Hippo pathway, which is activated by Yes-associated protein (YAP) through binding to two separated YAP regions of α1-helix and Ω-loop. Previous efforts have all been addressed on deriving peptide inhibitors from the YAP to target TEAD4. Instead, we herein attempted to rationally design a so-called 'YAP helixα1-trap' based on the TEAD4 to target YAP by using dynamics simulation and energetics analysis as well as experimental assays at molecular and cellular levels. The trap represents a native double-stranded helical hairpin covering a specific YAP-binding site on TEAD4 surface, which is expected to form a three-helix bundle with the α1-helical region of YAP, thus competitively disrupting TEAD4-YAP interaction. The hairpin was further stapled by a disulfide bridge across its two helical arms. Circular dichroism characterized that the stapling can effectively constrain the trap into a native-like structured conformation in free state, thus largely minimizing the entropy penalty upon its binding to YAP. Affinity assays revealed that the stapling can considerably improve the trap binding potency to YAP α1-helix by up to 8.5-fold at molecular level, which also exhibited a good tumor-suppressing effect at cellular level if fused with TAT cell permeation sequence. In this respect, it is considered that the YAP helixα1-trap-mediated blockade of Hippo pathway may be a new and promising therapeutic strategy against cancers.

Targeting of mutant-p53 and MYC as a novel strategy to inhibit oncogenic SPAG5 activity in triple negative breast cancer.

Triple negative breast cancer (TNBC) is an aggressive disease which currently has no effective therapeutic targets and prominent biomarkers. The Sperm Associated antigen 5 (SPAG5) is a mitotic spindle associated protein with oncogenic function in several human cancers. In TNBC, increased SPAG5 expression has been associated with tumor progression, chemoresistance, relapse, and poor clinical outcome. Here we show that high SPAG5 expression in TNBC is regulated by coordinated activity of YAP, mutant p53 and MYC. Depletion of YAP or mutant p53 proteins reduced SPAG5 expression and the recruitment of MYC onto SPAG5 promoter. Targeting of MYC also reduced SPAG5 expression and concomitantly tumorigenicity of TNBC cells. These effects of MYC targeting were synergized with cytotoxic chemotherapy and markedly reduced TNBC oncogenicity in SPAG5-expression dependent manner. These results suggest that mutant p53-MYC-SPAG5 expression can be considered as bona fide predictors of patient's outcome, and reliable biomarkers for effective anticancer therapies.

Focal Adhesion Maturation Responsible for Behavioral Changes in Human Corneal Stromal Fibroblasts on Fibrillar Substrates.

The functioning of the human cornea heavily relies on the maintenance of its extracellular matrix (ECM) mechanical properties. Within this context, corneal stromal fibroblasts (CSFs) are essential, as they are responsible for remodeling the corneal ECM. In this study, we used a decellularized human amniotic membrane (dHAM) and a custom fibrillar collagen film (FCF) to explore the effects of fibrillar materials on human CSFs. Our findings indicate that substrates like FCF can enhance the early development of focal adhesions (FAs), leading to the activation and propagation of mechanotransduction signals. This is primarily achieved through FAK autophosphorylation and YAP1 nuclear translocation pathways. Remarkably, inhibiting FAK autophosphorylation negated the observed changes. Proteome analysis further confirmed the central role of FAs in mechanotransduction propagation in CSFs cultured on FCF. This analysis also highlighted complex signaling pathways, including chromatin epigenetic modifications, in response to fibrillar substrates. Overall, our research highlights the potential pathways through which CSFs undergo behavioral changes when exposed to fibrillar substrates, identifying FAs as essential mechanotransducers.

Effects of Pulsed Electromagnetic Field Treatment on Skeletal Muscle Tissue Recovery in a Rat Model of Collagenase-Induced Tendinopathy: Results from a Proteome Analysis.

Tendon disorders often result in decreased muscle function and atrophy. Pulsed Electromagnetic Fields (PEMFs) have shown potential in improving tendon fiber structure and muscle recovery. However, the molecular effects of PEMF therapy on skeletal muscle, beyond conventional metrics like MRI or markers of muscle decline, remain largely unexplored. This study investigates the metabolic and structural changes in PEMF-treated muscle tissue using proteomics in a rat model of Achilles tendinopathy induced by collagenase. Sprague Dawley rats were unilaterally induced for tendinopathy with type I collagenase injection and exposed to PEMFs for 8 h/day. Gastrocnemius extracts from untreated or PEMF-treated rats were analyzed with LC-MS/MS, and proteomics differential analysis was conducted through label-free quantitation. PEMF-treated animals exhibited decreased glycolysis and increased LDHB expression, enhancing NAD signaling and ATP production, which boosted respiratory chain activity and fatty acid beta-oxidation. Antioxidant protein levels increased, controlling ROS production. PEMF therapy restored PGC1alpha and YAP levels, decreased by tendinopathy. Additionally, myosins regulating slow-twitch fibers and proteins involved in fiber alignment and force transmission increased, supporting muscle recovery and contractile function. Our findings show that PEMF treatment modulates NAD signaling and oxidative phosphorylation, aiding muscle recovery through the upregulation of YAP and PGC1alpha and increasing slow myosin isoforms, thus speeding up physiological recovery.

Oxidative stress reprograms the transcriptional coactivator Yki to suppress cell proliferation.

The transcriptional coactivator Yorkie (Yki) regulates organ size by promoting cell proliferation. It is unclear how cells control Yki activity when exposed to harmful stimuli such as oxidative stress. In this study, we show that oxidative stress inhibits the binding of Yki to Scalloped (Sd) but promotes the interaction of Yki with another transcription factor, forkhead box O (Foxo), ultimately leading to a halt in cell proliferation. Mechanistically, Foxo normally exhibits a low binding affinity for Yki, allowing Yki to form a complex with Sd and activate proliferative genes. Under oxidative stress, Usp7 deubiquitinates Foxo to promote its interaction with Yki, thereby activating the expression of proliferation suppressors. Finally, we show that Yki is essential for Drosophila survival under oxidative stress. In summary, these findings suggest that oxidative stress reprograms Yki from a proliferation-promoting factor to a proliferation suppressor, forming a self-protective mechanism.

TAOK1-mediated regulation of the YAP/TEAD pathway as a potential therapeutic target in heart failure.

BACKGROUND: This study aimed to determine the roles of interleukin (IL)-17, TAO kinase 1 (TAOK1), and NOD-like receptor protein 3 (NLRP3) in cardiomyocyte pyroptosis and proliferation. METHODS: The IL-17-treated H9C2 cells were used as in vitro heart failure (HF) models. These cells were subjected to TAOK1 overexpression or knockdown and treated with BMS-986299 (NLRP3 inflammasome agonist), MCC950 (NLRP3 inflammasome inhibitor), or verteporfin (Yes-associated protein [YAP] inhibitor). Thereafter, their pyroptosis, proliferative capacity, and gene and protein expression levels were detected. Doxorubicin-induced HF rats were used as in vivo models and subjected to TAOK1 overexpression. Thereafter, their myocardial pathology, NLRP3 inflammasome-mediated pyroptosis, and YAP/TEAD pathway function were evaluated. RESULTS: IL-17 treatment increased the pyroptosis and decreased the proliferative capacity of H9C2 cells. Additionally, IL-17 treatment inducedto the activation of the NLRP3 inflammasomes and inhibition of the YAP/TEAD pathway in the H9C2 cells. Moreover, the IL-17-mediated effects on the H9C2 cells were alleviated by TAOK1 overexpression and augmented by TAOK1 knockdown. Furthermore, treatment with BMS-986299 or verteporfin affected the pyroptosis, proliferative capacity, and NLRP3 inflammasome activation of the H9C2 cells independently of TAOK1 expression. In the doxorubicin-induced HF rat model, TAOK1 overexpression mitigated myocardial injury, suppressed NLRP3 inflammasome pathway activation, and restored the YAP/TEAD pathway activity. CONCLUSION: TAOK1 played a crucial role in regulating IL-17-mediated increase in the pyroptosis and decrease in the proliferation of cardiomyocytes by regulating the activities of the NLRP3 inflammasomes and the YAP/TEAD pathway.

[Dobutamine Enhances the Targeted Inhibitory Effect of Quizartinib on FLT3-ITD Mutant Acute Myeloid Leukemia].

OBJECTIVE: To observe the inhibitory effect of dobutamine on proliferation of FLT3-ITD mutated acute myeloid leukemia (AML) cells and explore the feasibility of dobutamine as a monotherapy or in combination with quizartinib for the treatment of this type of AML. METHODS: FLT3-ITD mutant cell lines MOLM13 and MV4-11 were cultured in vitro and divided into control group, dobutamine treatment group, quizartinib treatment group, and dobutamine combined with quizartinib treatment group. Cell viability, ROS levels, and apoptosis rate were detected by CCK-8, Flow cytometry, respectively, as well as the expression of YAP1 protein by Western blot. RESULTS: Both dobutamine and quizartinib inhibited the proliferation of FLT3-ITD mutant AML cell lines. Compared with the control group, the dobutamine group exhibited a significant increase in ROS levels (P < 0.01), an increase in apoptosis rates (P < 0.05), and a decrease in YAP1 protein expression (P < 0.01), and decreased YAP1 expression (P < 0.05). CONCLUSION: Dobutamine as a monotherapy can inhibit theproliferation of FLT3-ITD mutated AML cells, inducing apoptosis. Additionally, the combination of quizartinib enhances the targeted inhibitory effect on FLT3-ITD mutated AML. The mechanism may involve the inhibition of YAP1 protein expression in AML cells of this type, leading to an increase in ROS levels and exerting its anti-tumor effects.

Machine learning based identification potential feature genes for prediction of drug efficacy in nonalcoholic steatohepatitis animal model.

BACKGROUND: Nonalcoholic Steatohepatitis (NASH) results from complex liver conditions involving metabolic, inflammatory, and fibrogenic processes. Despite its burden, there has been a lack of any approved food-and-drug administration therapy up till now. PURPOSE: Utilizing machine learning (ML) algorithms, the study aims to identify reliable potential genes to accurately predict the treatment response in the NASH animal model using biochemical and molecular markers retrieved using bioinformatics techniques. METHODS: The NASH-induced rat models were administered various microbiome-targeted therapies and herbal drugs for 12 weeks, these drugs resulted in reducing hepatic lipid accumulation, liver inflammation, and histopathological changes. The ML model was trained and tested based on the Histopathological NASH score (HPS); while (0-4) HPS considered Improved NASH and (5-8) considered non-improved, confirmed through rats' liver histopathological examination, incorporates 34 features comprising 20 molecular markers (mRNAs-microRNAs-Long non-coding-RNAs) and 14 biochemical markers that are highly enriched in NASH pathogenesis. Six different ML models were used in the proposed model for the prediction of NASH improvement, with Gradient Boosting demonstrating the highest accuracy of 98% in predicting NASH drug response. FINDINGS: Following a gradual reduction in features, the outcomes demonstrated superior performance when employing the Random Forest classifier, yielding an accuracy of 98.4%. The principal selected molecular features included YAP1, LATS1, NF2, SRD5A3-AS1, FOXA2, TEAD2, miR-650, MMP14, ITGB1, and miR-6881-5P, while the biochemical markers comprised triglycerides (TG), ALT, ALP, total bilirubin (T. Bilirubin), alpha-fetoprotein (AFP), and low-density lipoprotein cholesterol (LDL-C). CONCLUSION: This study introduced an ML model incorporating 16 noninvasive features, including molecular and biochemical signatures, which achieved high performance and accuracy in detecting NASH improvement. This model could potentially be used as diagnostic tools and to identify target therapies.

Radiation-induced YAP/TEAD4 binding confers non-small cell lung cancer radioresistance via promoting NRP1 transcription.

Despite the importance of radiation therapy as a non-surgical treatment for non-small cell lung cancer (NSCLC), radiation resistance has always been a concern, due to poor patient response and prognosis. Therefore, it is crucial to uncover novel targets to enhance radiotherapy and investigate the mechanisms underlying radiation resistance. Previously, we demonstrated that NRP1 was connected to radiation resistance in NSCLC cells. In the present study, bioinformatics analysis of constructed radiation-resistant A549 and H1299 cell models revealed that transcription coactivator YAP is a significant factor in cell proliferation and metastasis. However, there has been no evidence linking YAP and NRP1 to date. In this research, we have observed that YAP contributes to radiation resistance in NSCLC cells by stimulating cell proliferation, migration, and invasion. Mechanistically, YAP dephosphorylation after NSCLC cell radiation. YAP acts as a transcription co-activator by binding to the transcription factor TEAD4, facilitating TEAD4 to bind to the NRP1 promoter region and thereby increasing NRP1 expression. NRP1 has been identified as a new target gene for YAP/TEAD4. Notably, when inhibiting YAP binds to TEAD4, it inhibits NRP1 expression, and Rescue experiments show that YAP/TEAD4 influences NRP1 to regulate cell proliferation, metastasis and leading to radiation resistance generation. According to these results, YAP/TEAD4/NRP1 is a significant mechanism for radioresistance and can be utilized as a target for enhancing radiotherapy efficacy.

Stepwise-targeting and hypoxia-responsive liposome AMVY@NPs carrying siYAP and verteporfin for glioblastoma therapy.

BACKGROUND: The Hippo pathway is a conserved tumour suppressor signalling pathway, and its dysregulation is often associated with abnormal cell growth and tumorigenesis. We previously revealed that the transcriptional coactivator Yes-associated protein (YAP), the key effector of the Hippo pathway, is a molecular target for glioblastoma (GBM), the most common malignant brain tumour. Inhibiting YAP with small interfering RNA (siYAP) or the specific inhibitor verteporfin (VP) can diminish GBM growth to a certain degree. RESULTS: In this study, to enhance the anti-GBM effect of siYAP and VP, we designed stepwise-targeting and hypoxia-responsive liposomes (AMVY@NPs), which encapsulate hypoxia-responsive polymetronidazole-coated VP and DOTAP adsorbed siYAP, with angiopep-2 (A2) modification on the surface. AMVY@NPs exhibited excellent blood‒brain barrier crossing, GBM targeting, and hypoxia-responsive and efficient siYAP and VP release properties. By inhibiting the expression and function of YAP, AMVY@NPs synergistically inhibited both the growth and stemness of GBM in vitro. Moreover, AMVY@NPs strongly inhibited the growth of orthotopic U87 xenografts and improved the survival of tumour-bearing mice without adverse effects. CONCLUSION: Specific targeting of YAP with stepwise-targeting and hypoxia-responsive liposome AMVY@NPs carrying siYAP and VP efficiently inhibited GBM progression. This study provides a valuable drug delivery platform and creative insights for molecular targeted treatment of GBM in the future.